Recording sheets with lightfastness-enhancing siloxanes

Abstract

Disclosed is a recording sheet which comprises a substrate and an image-receiving coating situated on at least one surface of the substrate, said image-receiving coating being suitable for receiving images of an aqueous ink, said image-receiving coating comprising a lightfastness agent which is a polysiloxane having thereon a hydrophilic moiety and a lightfastness moiety.

What is claimed is:  
     
       1. A recording sheet which comprises a substrate and an image-receiving coating situated on at least one surface of the substrate, said image-receiving coating being suitable for receiving images of an aqueous ink, said image-receiving coating comprising a lightfastness agent of one of the formulae                    
       wherein R 1 , R 2 , R 3 , R 4 , R 9 , R 6 , R 7 , R 8 , R 9 , and R 10  each, independently of the others, is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, R 11  and R 12  each, independently of the others, is an alkylene group, an arylene group, an arylalkylene group, or an alkylarylene group, G is a cationic moiety, A is an anionic moiety, n is an integer representing the number of repeat —OSi(R 7 )(R 8 )— monomer units, a is an integer representing the number of repeat —OSi(R 10 )(R 12 -lightfastness moiety)— monomer units, and c is an integer representing the number of repeat —OSi(R 9 )(R 11 -hydrophilic moiety)— monomer units. 
     
     
       2. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula I and the lightfastness moiety is a 2-(3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl) group, a hydroxybenzophenone group, a hydroxybenzoic acid group, an alkoxybenzoic acid group, an ester of a substituted benzoic acid, a (hydroxyphenyl)-1,3,5-triazine group, a phenylbenzimidazole sulfonic acid group, or a reducing sugar group. 
     
     
       3. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula I and the lightfastness moiety is of one of the formulae                    
       wherein R is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group,                    
       wherein R 1  and R 2  each, independently of the other, is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group,                    
     
     
       4. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula I and the lightfastness moiety is of one of the formulae                    
     
     
       5. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula II or Formula V and the lightfastness moiety is an anionic (hydroxyphenyl)benzotriazole, an anionic hydroxybenzophenone, an anionic hydroxybenzoic acid, an anionic alkoxybenzoic acid, an anionic ester of a substituted benzoic acid, or an anionic (hydroxyphenyl)-1,3,5 triazine. 
     
     
       6. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula II or Formula V and the lightfastness moiety is of one of the formulae                    
       wherein R is an alkyl group,                    
       wherein R is an alkyl group,                    
       wherein R is an alkyl group,                    
       wherein R is an alkyl group,                    
       wherein A is an anionic substituent. 
     
     
       7. A recording sheet according to  claim 6  wherein A is a carboxylate group, a moiety substituted with a carboxylate group, a sulfonate group, a moiety substituted with a sulfonate group, a phosphonate group, or a moiety substituted with a phosphonate group. 
     
     
       8. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula II or Formula V and the lightfastness moiety is of one of the formulae                    
     
     
       9. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula II or Formula V and the lightfastness moiety is 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid; 2,2′-dihydroxy-4,4′dimethoxybenzophenone-5-sulfonic acid; 2,3-dimethoxybenzoic acid; 3,4-dimethoxybenzoic acid; 3,5-dimethoxybenzoic acid; 2,5-dimethoxybenzoic acid; 2,6-dimethoxybenzoic acid 3,4-dimethoxybenzenesulfonic acid; 3,4,5-trimethoxybenzoic acid; 2,4,5-trimethoxybenzoic acid; 4,5-dimethoxyphthalic acid; 2,3-bis-isopropylidenedioxybenzoic acid; 2,3-bis-(carboxymethyloxy)-benzoic acid; 2,5-dihydroxyphenylacetic acid; or mixtures thereof. 
     
     
       10. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula II or Formula V and the lightfastness moiety is of one of the formulae                  
                   
     
     
       11. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula III or Formula IV and the lightfastness moiety is a 2-(3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl) quaternary compound, a hydroxybenzophenone quaternary compound, or a quaternary ammonium derivative of a dialkylaminobenzoate. 
     
     
       12. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula III or Formula IV and the lightfastness moiety is of one of the formulae                  
                   
       wherein R 5  and R 6  each, independently of the other, is an alkyl group or an arylalkyl group, R 1  is an alkylene group, an arylalkylene group, or a polyalkyleneoxy group, and R 2 , R 3 , and R 4  each, independently of the others, is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, an alkoxy group, or a polyalkyleneoxy group. 
     
     
       13. A recording sheet according to  claim 1  wherein the lightfastness agent is of Formula III or Formula IV and the lightfastness moiety is of one of the formulae                    
     
     
       14. A recording sheet according to  claim 1  wherein the hydrophilic moiety is a polyoxyalkylene chain, a poly(2-alkyloxazoline), or a poly(ethyleneimine) chain. 
     
     
       15. A recording sheet according to  claim 1  wherein the hydrophilic moiety is a polyethylene oxide chain, a polypropylene oxide chain, a polybutylene oxide chain, or a copolymer of two or more of ethylene oxide, propylene oxide, and butylene oxide. 
     
     
       16. A recording sheet according to  claim 1  wherein the hydrophilic moiety is (a) of one of the formulae 
       
         
           —(C x H 2x O) n H  
         
       
       and 
       
         
           —(OC x H 2x ) n OH  
         
       
       wherein x, independently in each single repeat alkylene oxide unit, is an integer of 2, 3, or 4 and n is an integer representing the number of repeat alkylene oxide units, (b) of the formula                    
       wherein R is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, and n is an integer representing the number of repeat monomer units, or (c) of the formula                    
       wherein n is an integer representing the number of repeat monomer units. 
     
     
       17. A recording sheet according to  claim 1  wherein the lightfastness agent is poly(dimethylsiloxane-co-methyl (carboxyltrimethylsilylpentanoyl)siloxane)-graft-methoxypolyethylene glycol, poly(dimethylsiloxane-co-methyl(3-propyl(2-hydroxybenzophenone) siloxane)-graft-methoxypolyethylene glycol), Poly(dimethylsiloxane-co-methyl(2-(3-2H-benzotriazol-2-yl)-4-hydroxyphenyl)ethylpentanoate) siloxane)-graft-methoxypolyethylene glycol), the quaternary ammonium hydroxybenzotriazole salt of poly(dimethylsiloxane-co-methyl (carboxypentanoyl) siloxane)-graft-methoxypolyethylene glycol), the 2-hydroxy-4-methoxybenzophenone-5-sulfonate salt of poly(dimethylsiloxane-co-methyl(3-trimethylaminopropyl) siloxane), or a mixture thereof. 
     
     
       18. A process which comprises (a) applying to a substrate a lightfastness agent of one of the formulae                    
       wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , and R 10  each, independently of the others, is an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, R 11  and R 12  each, independently of the others, is an alkylene group, an arylene group, an arylalkylene group, or an alkylarylene group, G is a cationic moiety, A is an anionic moiety, n is an integer representing the number of repeat —OSi(R 7 )(R 8 )— monomer units, a is an integer representing the number of repeat —OSi(R 10 )(R 12 -lightfastness moiety)— monomer units, and c is an integer representing the number of repeat —OSi(R 9 )(R 11 -hydrophilic moiety)— monomer units; (b) subsequent to step (a), incorporating into an ink jet printing apparatus an ink composition which comprises water and a colorant; and (c) causing droplets of the ink composition to be ejected in an imagewise pattern onto the substrate. 
     
     
       19. A process according to  claim 18  wherein the printing apparatus employs a thermal ink jet process wherein the ink in the nozzles is selectively heated in an imagewise pattern, thereby causing droplets of the ink to be ejected in imagewise pattern. 
     
     
       20. A process according to  claim 18  wherein the printing apparatus employs a piezoelectric ink jet process wherein droplets of the ink are caused to be ejected in imagewise pattern by oscillations of piezoelectric vibrating elements.